Spark plug shield



-Aug. 17, 1948. G. G. BURRELL Erm.

sAnx PLUG SHIELD Filed March 8, 1946 46E/VI ture shield shown in Figures 1 Patented Aug. 17, 1948- UNITED sinful-iasv PATEN T GFFICE 2,447,157 SPARK PLUG SHIELD George G. Burrell Iowa; said Leo Burrell rell, Cedar Rapids, Iowa Application March 8, 1946, Serial No.

1o Claims. (ci. 174-70 'I'hisinvention` relates to spark plugs, and particularly to means for moisture prooiing the electrical connection to such plugs.

Although numerous methods and devices have been suggested for moisture proong spark plugs, most oi.' such devices require a complicated structure and many of them involve the use of acomfor protecting the i electrical connection to the plug from shorting out and becoming in-operative d sation or other causes. A

Another object of our invention is to provide a. device which may be e to rain or condenspark plug of ordinary conporcelain insulator and Leo Burrell, assignor to Cedar Rapids, Kittie P. Bur- 2 at the top of the insulator, is a portion oi the electrical conductor which extends downwardly through the center of the insulator to terminate which may Other and further features and objects of the invention will be more apparent to those skilled in the art upon a consideration of the accompanying drawings and following specification, wherein bodied in our invention.

Figure4 is a in section of a view partly in elevation and vpartly slightly modiied form of the moisand 2, and

Figure 5 is aview in elevation, partly in secin the ring point 6.

In the majority of such plugs the porcelain insulator 4 is provided with one or more annular A-pointed stylus 8 is provided with a tapped opening 9, on its under side, to permit attachment to the central terminal .5. This stylus, being adapted to penetrate the lower end of the iger end of the cable as indicated at I2.

The conical moisture shield I3, preferably of molded plastic or the like. is apertured at its uprugation or enlargement.

With the various as shown in Figure 2,

provide a seal against the curved under surface of the porcelain enlargement 1.

A modied form of sealing washer such as illustratedinFlgux-eimaybeemployedinthestructure of Figure 2. split diagonally as is composed each member actually in itself and each split radially as indicated at 23 and 24. These cuts 23 and 24 are staggered radially to provide a leak-proof joint.

The slightly modiiled form of our invention as illustrated in Figure 4 is substantially the same as the structure shown in Figures 1 and 2 in that the structure includes the complete spark plug with the porcelain 4, the upper terminal 5, the enlargement 1 on top of the porcelain, and the cable I0. The moisture shield 2l is of somewhat the structure shown in Figwith the opening 24 through its upper portion i0, but the inner cavity 21 tapers toward the hole for the reception of the cable ignition cable.

26 in such a manner that the lower end of the cable i0 is wedged against the tapered side walls of the cavity `21 as well as in the hole 26. The lower end of the moisture shield 2l is threaded externally as at 28, to receive the internally threaded, lower insulating shield or sleeve 20. This sleeve is flanged inwardly at its bottom, as at 30, so as to carry the sealing washer 2|. This sealing washer is split diagonally, as shown at $2, or a double washer such as we have shown in Figure 3 is employed to permit its installation over the enlarged portion of the spark plug porcelain. Both the moisture shield 25 and the sleeve 29 are preferably provided with drip flanges 33 and 34 respectively.

Figure 5 illustrates a form of our invention adapted for use with spark plugs of the type having a porcelain with a smooth cylindrical upper end-and without the corrugations or enlargements shown in Figures 2 and 3. Such a plug is indicated at 35 with the porcelain insulator 30 and upper terminal 31.

This form of moisture shield generally comprises the upper shield 3l. the lower shield 3l, the gasket 40 and the stylus 4 i. The upper shield 38 is in the form of a hollow shell apertured at its top, as at 42, to receive the ignition cable 4I and threaded internally at its lower end, as shown at `44. This lower end engages over the externally threaded upper end of the lower shield I I. The lower shield is cylindrical with its lower end open for reception over the upper end of the porcelain 3B and the upper wall 45 of the lower shield is apertured, as at 48, to permit the plug terminal to pass upwardly through the shield.

The interior of the lower shield is provided with a shoulder 41 against which the washer 4l is adapted to bear. The stylus 4i is drilled and tapped for the upper terminal as in Figure 2, but its lower end is preferably cut back to provide a shoulder for engaging the upper wall of the lower shield. g

The gasket 4l has an internal diameter suitable to the porcelain over which it is to be placed and, when assembled as illustrated and -forced down over the porcelain by screwing the stylus into place, the gasket will seal the upper end of the porcelain.

The electrical connection between the stylus 4| and the cable 43 is, of course, sealed against molsture'when the upper shield l. is threaded onto the lower shield 45.

Although we have described specinc embodiments of our invention. it is apparent that modiiications thereof may be made by those skilled in the art. Buch modifications may be made witb- 4 out departing from the spirit and scope of our invention as set forth in the appended claims.

What we claim is: l. In a moisture shield for a spark plug having a porcelain insulator and a terminal at the top thereof. an upper insulating shield having an opening through the top thereof for receiving an means including a stylus for exa sealing gasket engaged by and adapted to be forced by the lower shield member into contact with the porcelain insulator whereby a moisture sealed chamber is provided above the said sealing gasket and within the upper and lower insulating shields.

2. In a moisture shield for a spark plug having a porcelain insulator, a shield. a cable received through an opening in the top of the shield, a pointed stylus, means forcing the stylus into the cable to wedge and seal it within the opening. and

means cooperating with said shield to provide a moisture-proof chamber enclosing the top portion of the insulator, said means including a split washer associated with the shield at its lower end and resiliently engaging the porcelain insulator.

3. For use in .combination with an insulated ignition cable and a spark plug including an insulator having an annular enlargement thereon and an electrode disposed centrally of the insulator; a pointed stylus secured to ,the said electrode. a hollow shield having an opening in the top thereof for receiving the cable, means forcing the said stylus into the end of the cable to expand and seal the cable within the shield opening said means comprising a sleeve threadedly engaged to the said shield and a split washer engaged by the said sleeve and mounted over and engaged beneath the insulator enlargement.

4. The combination of a cable and a spark plug including an insulator and an electrode disposed centrally of the insulator, a stylus secured to the electrode, a shield having an opening through the top thereof for receiving the cable, means forming a shoulder adiacentthe top of the insulator, a split washer engageable beneath the shoulder and 'a sleeve engaging the said washer and threadedly engaged with the said shield, the said stylus adapted to make contact with the cable and to wedge and seal it in place within the shield opening.

5. In a moisture shield for spark plugs, the combination with a spark plug insulator, of a shield for covering the upper portion of the said insulator, an enlargement provided adjacent the top of the insulator and means for sealing the lower end of the shield including a washer split to permit it to be installed over the insulator enlargement and adapted to engage the said enlargement on its under side.

6. In a moisture shield for spark plugs, the combination with a spark plug insulator having adjacent the top thereof, of a the upper portion of the said insulator, and means for sealing the shield at its lower end including a washer, split angularly to permit it to be installed over the insulator enlargement and adapted to engage the said enlargement on its under side.

'7. For use in combination with an insulated ignition cable and a spark plug including a porcelain insulator having an annular enlargement thereon and an electrode disposed centrally thereof, a pointed stylus removably secured to the upper portion of which upper end of said electrode, a hollow and generally downwardly and outwardly ilaring moisture shield of an insulating material, the said shield having an opening through its top of substantially the same diameter. as that of the cable, the

washer whereby engaging the sleeve to the shield will seal the said washer against the enlargement and force the stylus into the cable to enlarge it and wedge and seal it within the opening in the shield. Y

9. In a moisture shield for a spark plug .having an upper terminal and a porcelain insulator the is of generally tapering diameter than the largest diameter of the porce lain. adapted to rest against the said shoulder, a stylus engageable withA the upper terminal and within the opening in the top of the upper shield.

BURRELL GEORGE G. LEO BURRELL, REFERENCES CITED The following referencesare oi' record in the i ille ot this patent:

shape, a hollow lower shield having an opening 40 through the top thereof adapted to be received over the terminal, the lower shield having ashoulder` on the interior thereof, a gasket, having an opening through the center thereof of lesserI v UNITED STATES f PATENTS up, y 

